Vacuum process device and vacuum process method

ABSTRACT

An efficient method of controlling transportation in a linear tool type vacuum process device in a state that a length of time required for a process is not stable. For each process chamber, the number of unprocessed wafers that are in process or are being transported to the process chamber is counted, and in deciding a transport destination of a wafer, when the number of unprocessed wafers is equal to or larger than a charge limit amount, a transport destination of a wafer is decided excluding the process chamber. Also, a wafer holding mechanism on a transport path to a process chamber is reserved, and a transport destination of a processed member to be transported next is decided according to a status of reservation.

CLAIM OF PRIORITY

The present application claims priority from Japanese patent applicationJP 2011-117755 filed on May 26, 2011, the content of which is herebyincorporated by reference into this application.

BACKGROUND OF THE INVENTION

1) Field of the Invention

The present invention relates to a vacuum process device, and inparticular relates to a method of transporting semiconductor processedmembers (hereinafter, wafers) between process chambers and the like in asemiconductor process device.

2) Description of the Related Arts

A semiconductor process device, and in particular a device thatprocesses wafers that are a process subject in a reduced pressure hasbeen required to be more efficient in processing the process subject asprocesses become more minute and refined. As a result, in recent years,a multi-chamber device provided with a plurality of process chambersconnected therein has been developed, and improvements have been made tomake productivity per installation area of a clean room more efficient.In such a device that performs processes with a plurality of processchambers provided therein, a gas in each process chamber and thepressure are adjusted to a reduced pressure, and a transport chamberprovided with a robot and the like for transporting wafers is connectedthereto.

As such a multi-chamber device, a device with a cluster tool structurein which process chambers are connected radially along circumferences oftransport chambers is widely used. However, the cluster tool type devicerequires a large installation area, and in particular the installationarea has been becoming further larger as wafers are becoming larger indiameters in recent years. To address this problem, a device with alinear tool structure has appeared (for example, Japanese UnexaminedPatent Application Publication No. 2007-511104). A characteristic of alinear tool is that the structure has a plurality of transport chambers,a process chamber is connected to each transport chamber, and thetransport chambers are connected with each other directly or with spacesfor receiving and passing wafers (hereinafter, buffer rooms)therebetween.

Although the linear tool structure has been proposed to make aninstallation area smaller, other proposals have been made to furtherimprove productivity. Shortening of a process time and efficienttransportation are important in improving productivity, and inparticular many efficient transport methods have been proposed. Knownrepresentative methods use scheduling. The methods using scheduling arethat a transport operation is decided in advance, and transportation isperformed based on the decision. In an example of methods proposed, atransport operation is decided by allocating earlier, as a transportdestination, a process chamber with a shorter process completion time(for example, Japanese Patent Application Laid-open Publication No.10-189687).

The methods using scheduling can realize high productivity under acondition that lengths of time for etching and deposition are stablearound standard lengths of time required for the processes. However, aprocess time often is not stable and becomes severalfold longer thanstandard lengths of time required for the processes when a new productis processed or processing conditions for wafers change. In such asituation, when a process time is extended in a process chamber among aplurality of process chambers, a wafer planned to be processed in theprocess chamber cannot be transported as scheduled, and has to wait inthe device; as a result, a transport path of another wafer planned to beprocessed in another process chamber is blocked, and thus productivityis decreased.

Explaining specifically, for example, suppose that there are two processchambers, a process in a process chamber A is planned to end in 20seconds, and a process in a process chamber B is planned to end in 50seconds. At this time, it is supposed that a wafer W1 planned to beprocessed next in the process chamber A is waiting in a load lock. Ifthe process in the process chamber A ends in 20 seconds as scheduled,the wafer W1 is taken out of the load lock, and the process is performedon the wafer W1 in the process chamber A. If this is the case, the loadlock is emptied, and a wafer W2 to be processed next in the processchamber B can be taken in; accordingly, as soon as a process in theprocess chamber B ends, the wafer W2 can be processed in the processchamber B. However, if the process in the process chamber A does not endin 20 seconds as scheduled, the wafer W1 waiting in the load lockremains occupying the load lock, and the wafer W2 cannot enter the loadlock. Accordingly, the process in the process chamber A is prolonged,and even if the process in the process chamber B ends earlier, the waferW2 planned to be processed next in the process chamber B cannot betransported to the process chamber B, and cannot be processed.Therefore, productivity decreases.

As a solution for a case that a wafer planned to be processed in aprocess chamber is not transported as scheduled, and interferes withtransportation of another wafer planned to be processed in anotherprocess chamber, a method of, when a wafer that cannot be transported asscheduled emerges, rescheduling a transport schedule by collecting awafer that is not transported as scheduled or moving the wafer to aspace for temporary evaluation has been proposed (Japanese UnexaminedPatent Application Publication No. 2002-506285).

SUMMARY OF THE INVENTION

The above-described conventional techniques have problems below.

Even if a transport schedule is rescheduled to mitigate a decrease inproductivity in a situation that a process time is not stable,operations that are not necessary originally of collecting wafers ortransporting the wafers to a space for temporary evacuation areperformed, a decrease in productivity cannot be avoided, and thus thiscannot necessarily be said to be an efficient transport method.

Also, an efficient transport method differs depending on a process stepof a wafer in some cases. A process step may complete by performing aprocess once in a process chamber, and otherwise a process step maycomplete by performing a process several times. Furthermore, anefficient transport method differs depending on an operation condition.In one operation condition, a process chamber where a process on a waferis planned can be changed freely anytime, and otherwise in anotheroperation condition, a process chamber where a process on a wafer isplanned cannot be changed once the wafer starts to be transported froman initial position. An operation condition that a process chamber wherea process on a wafer is planned can be changed freely anytime is appliedwhen process conditions such as types of gases used for processes arethe same for a plurality of process chambers, and qualities of wafersafter the processes do not differ even if the wafers are processed inany process chamber. Also, an operation condition that a process chamberwhere a process on a wafer is planned cannot be changed once a waferstarts to be transported from an initial position is applied when,although process conditions such as types of gases used for processesare the same for a plurality of process chambers, process conditions areslightly adjusted depending on a wafer-specific condition such as a filmthickness once a process chamber where a process on a wafer is plannedis decided or when process conditions such as types of gases used forprocesses differ for process chambers.

An object of the present invention is to provide a linear tool typesemiconductor process device with a high transport efficiency and a highthroughput in which, at a process step that completes by performing aprocess once in a process chamber, under an operation condition that aprocess chamber where a process on a wafer is planned cannot be changedonce transportation of the wafer is started from an initial position, ina situation that a process time is not stable, a wafer planned to beprocessed in a process chamber does not interfere with transportation ofanother wafer planned to be processed in another process chamber.

Even if a process time of a process chamber is prolonged, it iscontrolled not to block a transport path of a wafer transported toanother process chamber by restricting the number of unprocessed wafersto be charged to each process chamber.

A device has, as units that restrict the number of unprocessed wafers tobe charged to each process chamber: a unit that reserves for eachprocess chamber and for each wafer a wafer holding mechanism in a loadlock or buffer room on a transport path of the wafer to the processchamber before starting the transportation; a unit that restrictsreservation of a holding mechanism in the common load lock or bufferroom for a wafer planned to be transported to the same process chamber;a unit that restricts reservation so that all holding mechanisms in eachload lock or buffer room are not reserved; and a unit that cancelsreservation of a reserved holding mechanism when a process of atransport destination process chamber of the holding mechanism ends.

Furthermore, the units that restrict the number of unprocessed wafers tobe charged to each process chamber do not charge a new unprocessed waferwhen all holding mechanisms in any load lock or buffer room are reservedor all but one of holding mechanisms are reserved.

The present invention can provide a semiconductor process device with ahigh transport efficiency and a high throughput in which, in a situationthat a process time is not stable, a wafer planned to be processed in aprocess chamber does not interfere with transportation of another waferplanned to be processed in another process chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a figure for explaining a gist of an entire configuration of asemiconductor process device;

FIG. 2 is a figure for explaining a configuration of a machine unit ofthe semiconductor process device;

FIG. 3 is a figure for explaining a structure of holding wafers of themachine unit of the semiconductor process device;

FIG. 4 is a flowchart for explaining an overall flow of an operationcontrol system of the semiconductor process device;

FIG. 5 is a figure for explaining a process of operation instructioncalculation, and input and output information;

FIG. 6 is a figure for explaining a process of transport destinationdeciding calculation, and input and output information;

FIG. 7 is a figure for explaining details of a process of unprocessedwafer amount calculation;

FIG. 8 is a figure for explaining details of a process ofallocation-subject process chamber calculation;

FIG. 9 is a figure for explaining details of a process of transportdestination calculation;

FIG. 10 is a figure for explaining a process of charge limit amountcalculation, and input and output information;

FIG. 11 is a figure for explaining details of a process of charge limitamount calculation;

FIG. 12 is a figure that shows an example of a display of a consoleterminal;

FIG. 13 is a figure that shows an example of device state information;

FIG. 14 is a figure that shows an example of process subjectinformation;

FIG. 15 is a figure that shows an example of process chamberinformation;

FIG. 16 is a figure that shows an example of transport destinationinformation;

FIG. 17 is a figure that shows an example of operation instructioninformation;

FIG. 18 is a figure that shows an example of operation instruction ruleinformation;

FIG. 19 is a figure that shows an example of operation sequenceinformation;

FIG. 20 is a figure that shows an example of unprocessed wafer amountinformation;

FIG. 21 is a figure that shows an example of allocation-subject processchamber information;

FIG. 22 is a figure that shows an example of charge limit amountinformation;

FIG. 23 is a figure that shows an example of holdable wafer amountinformation;

FIG. 24 is a figure that shows an example of block information;

FIG. 25 is a figure that shows a relationship between the machine unitand a block of the semiconductor process device;

FIG. 26 is a figure for explaining a process of transport destinationdeciding calculation, and input and output information;

FIG. 27 is a figure for explaining details of a process of reservationinformation calculation;

FIG. 28 is a figure for explaining details of a process ofallocation-subject process chamber calculation;

FIG. 29 is a figure that shows an example of transport destination pathinformation; and

FIG. 30 is a figure that shows an example of reservation information.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, an embodiment of the present invention is explained withreference to drawings.

A gist of an overall configuration of a semiconductor process deviceaccording to the present invention is explained with reference toFIG. 1. The semiconductor process device consists of, dividinggenerally, a machine unit 101 including process chambers and transportmechanisms, an operation control unit 102 and a console terminal 103.The machine unit 101 is configured with process chambers that canperform processes such as etching and deposition on wafers, andtransport mechanisms provided with robots that perform transportation ofwafers and the like. The operation control unit 102 is a controller thatcontrols operations of the process chambers and the transportmechanisms, and consists of an arithmetic operation unit 104 thatperforms arithmetic operation processes, and a storage unit 105 thatstores therein various kinds of information. The arithmetic operationunit 104 includes: a control mode setting unit 106 that switchesinternal processes of a control system depending on control modes of“manual” and “automatic” designated by a user; an operation instructioncalculating unit 107 that performs arithmetic operations for actuallyoperating the process chambers and the transport mechanisms; anunprocessed wafer amount calculating unit 108 that calculates anunprocessed wafer amount; an allocation-subject process chambercalculating unit 109 that calculates a process chamber to be a candidateof a transport destination of a wafer to be newly charged; a transportdestination calculating unit 110 that calculates a transport destinationprocess chamber of a wafer to be newly charged; a charge limit amountcalculating unit 111 that computes a charge limit amount that restrictsthe number of wafers planned to be charged to each process chamber; anda reservation calculating unit 124 that calculates to reserve a holdingmechanism for each wafer in a load lock and a buffer room that the wafergoes through when the wafer is transported to a process chamber. Also,the storage unit 105 stores therein device state information 112,process subject information 113, process chamber information 114,transport destination information 115, operation instruction information116, operation instruction rule information 117, operation sequenceinformation 118, unprocessed wafer amount information 119,allocation-subject process chamber information 120, charge limit amountinformation 121, holdable wafer amount information 122, blockinformation 123, reservation information 125, and transport destinationpath information 126. The console terminal 103 is for a user to input acontrol method and to confirm a state of the device, and is providedwith input equipment such as a keyboard, a mouse and a touch pen, and adisplay to output information. Also, the semiconductor process device isconnected to a host computer 127 through a network 128, and candownload, from the host computer 127 when needed, necessary informationsuch as recipes about types of gases to be used for processes,concentrations thereof, and the like, and standard lengths of timerequired for the processes.

Next, a configuration of a machine unit including process chambers andtransport mechanisms is explained with reference to FIG. 2. FIG. 2 is abird's-eye view of a top surface of the machine unit. The machine unitis generally divided into an atmosphere-side machine unit 232 and avacuum-side machine unit 233. The atmosphere-side machine unit 232 is apart that performs transportation and the like of wafers to take out andhouse the wafers from and in a cassette under the atmospheric pressure.The vacuum-side machine unit 233 is a part that transports wafers undera pressure reduced from the atmospheric pressure, and performs processesin the process chambers. A load lock 211 that is a part that increasesand reduces the pressure between the atmospheric pressure and vacuumwith wafers contained therein is provided between the atmosphere-sidemachine unit 232 and the vacuum-side machine unit 233.

The atmosphere-side machine unit 232 includes load ports 201, 202, analigner 234, an atmosphere robot 203, and a housing 204 that covers amovable area of the atmosphere robot 203. A cassette housing a processsubject wafer is placed in the load ports 201, 202. The atmosphere robot203 that has a hand that can hold wafers takes out a wafer housed in thecassette, and transport the wafer to the load lock 211, and otherwisetake out a wafer from the load lock 211, and house the wafer in thecassette. The atmosphere robot 203 can expand and contract, move up anddown, and rotate a robot arm, and furthermore can move inside thehousing 204 horizontally. Also, the aligner 234 is a machine foraligning orientations of wafers. The atmosphere-side machine unit 232 ismerely an example, and the device according to the present invention isnot limited to a device having two load ports, but the number of loadports may be larger than or smaller than two. In addition, the deviceaccording to the present invention is not limited to a device having oneatmosphere robot, but the device may have a plurality of atmosphererobots. In addition, the device according to the present invention isnot limited to a device having one aligner, but the device may have aplurality of aligners, or may not have an aligner.

The vacuum-side machine unit 233 includes process chambers 205, 206,207, 208, 209, 210, transport chambers 214, 215, 216, and buffer rooms212, 213. The process chambers 205, 206, 207, 208, 209, 210 are portionsthat perform processes such as etching and deposition on wafers. Theprocess chambers 205, 206, 207, 208, 209, 210 are connected to thetransport chambers 214, 215, 216 respectively, through gate valves 222,223, 226, 227, 230, 231. The gate valves 222, 223, 226, 227, 230, 231have valves that open and close, and can partition spaces inside theprocess chambers 205, 206, 207, 208, 209, 210 and spaces inside thetransport chambers 214, 215, 216, and connect the spaces.

The transport chambers 214, 215, 216 are provided with vacuum robots217, 218, 219, respectively. The vacuum robots 217, 218, 219 areprovided with hands that can hold wafers, and robot arms that can expandand contract, rotate, and move up and down to transport wafers to theload lock 211, the process chambers 205, 206, 207, 208, 209, 210, andthe buffer rooms 212, 213.

The buffer rooms 212, 213 are connected between the transport chambers214, 215, 216, and provided with mechanisms to hold wafers. With thevacuum robots 217, 218, 219 placing wafers in the buffer rooms 212, 213and taking out wafers therefrom, wafers can be passed between thetransport chambers 214, 215, 216. The buffer rooms 212, 213 areconnected to the transport chambers 214, 215, 216 respectively, throughgate valves 224, 225, 228, 229. The gate valves 224, 225, 228, 229 havevalves that open and close, and can partition spaces inside thetransport chambers 214, 215, 216 and spaces inside the buffer rooms 212,213, and connect the spaces. The vacuum-side machine unit 233 is merelyan example, and the device according to the present invention is notlimited to a device having six process chambers, but the number ofprocess chambers may be larger than or smaller than six. Also, it isexplained that in the device according to the present embodiment, twoprocess chambers are connected to a transport chamber, but the deviceaccording to the present invention is not limited to a device in whichtwo process chambers are connected to a transport chamber, but thenumber of process chambers connected to a transport chamber may be one,or three or larger. In addition, the device according to the presentinvention is not limited to a device having three transport chambers,but the number of transport chambers may be larger than or smaller thanthree. Also, it is explained in the present embodiment that the deviceis provided with gate valves between transport chambers and bufferrooms, but there may not be gate valves.

The load lock 211 is connected to the atmosphere-side machine unit 232and the vacuum-side machine unit 233 through gate valves 220, 221respectively, and can increase and reduce the pressure between theatmospheric pressure and vacuum with wafers contained therein.

Next, a structure of holding wafers is explained with reference to FIG.3 that is a bird's-eye view of a side surface of a machine unit. Waferscan be held in a load lock 305, and buffer rooms 310, 315. The load lock305 and the buffer rooms 310, 315 hold wafers in structures that canhold a plurality of wafers separately (hereinafter, holding steps). Itis physically possible to place wafers on any holding step, but in ageneral operation, only unprocessed wafers are placed on certain holdingsteps, and only processed wafers are placed on other holding steps. Thisis because corrosive gases used for processes are adhered to theprocessed wafers, and may remain on the holding steps. When theunprocessed wafers contact the gases, the wafers may be degenerated todegrade the qualities thereof. Accordingly, for example, when there arefour holding steps in a load lock as shown in FIG. 3, two holding stepsare for unprocessed wafer, and the remaining two holding steps are forprocessed wafers.

The reference numeral 301 designates a cassette placed in a load port;302 a housing that covers a movable area of an atmosphere robot; 303 theatmosphere robot; 307, 312 and 318 transport chambers; 308, 313 and 317a vacuum robot; 304, 306, 309, 311, 314 and 316 gate valves; and 319,320, 321, 322, 323, 324 and 325 wafers.

Next, an overall flow of an operation control system of thesemiconductor process device according to the present invention isexplained with reference to FIG. 4. It is assumed in the followingexplanation that, in the present invention, a linear tool handles only aprocess of a step that completes a process by performing a process in aprocess chamber, and once transportation of a wafer is started from aninitial position, the transportation is performed under an operationcondition that a process chamber where the process is planned cannot bechanged.

A user can select a control mode of “manual” or “automatic” with aconsole display 401. When “automatic” is selected here, the user canfurther select whether to perform control responding to a process timethat varies irregularly. Because a calculation process for controldiffers depending on the selected control mode and whether to respond toprocess time irregularity, a control mode setting unit 402 switches thecalculation process for control depending on the designated control modeand whether to respond to irregularity. For example, when “manual” isdesignated as the control mode, manual transport destination setting 403is executed. On the other hand, when “automatic” is designated as thecontrol mode, and not to respond to process time irregularity isdesignated, transport destination deciding calculation withoutresponding to process time irregularity 404 is executed. Also, on theother hand, when “automatic” is designated as the control mode, and torespond to process time irregularity is designated, transportdestination deciding calculation responding to process time irregularity405 is executed.

Each one of the arithmetic operation processes 403, 404, 405 is fordeciding a transport destination process chamber for a wafer to becharged, and outputting transport destination information 406. Inoperation command calculation 407, an operation command 409 is computedbased on the transport destination information 406 and device stateinformation 408, and a machine unit 410 performs an operation based onthe operation command 409. The state inside the device changes byperforming the operation, and the device state information 408 isupdated. Again, in the operation command calculation 407, the operationcommand 409 is computed based on the transport destination information406 and the device state information 408, and the machine unit 410performs a next operation.

Also, the arithmetic operation processes 404, 405 of deciding thetransport destination process chamber automatically are executed everytime a transport destination for a new process subject is decided, andthe transport destination information 406 is updated. For example, whenan atmosphere robot ends transportation of a wafer, and an operation ona new wafer can now be performed, a transport destination for the newwafer is calculated.

Because the present invention relates to an efficient control methodwhen the control mode is “automatic” and to respond to process timeirregularity is designated, the control method in such a case isexplained hereinafter. Accordingly, the transport destination decidingcalculation means the transport destination deciding calculationresponding to process time irregularity 405 hereinafter.

First, the operation command calculation 407 shown in FIG. 4 isexplained in detail with reference to FIG. 5. FIG. 5 is a figure thatshows a relationship between a process of the operation commandcalculation 407, and input and output information in detail. Theoperation command calculation 407 is configured with two arithmeticoperation processes of an operation instruction calculation 504 and anoperation command generation 507.

In the operation instruction calculation 504, device state information501, transport destination information 502 and operation instructionrule information 503 are input, and operation instruction information506 is output. The device state information 501 is exemplified in FIG.13, and shows the state of each portion, a number of a wafer that ispresent there, and the state of a process. For example, data “portion:load lock 221_step 1, state: vacuum, wafer number: W11, wafer state:unprocessed” represents the state of a first holding step of the loadlock 221, and means that the load lock is in vacuum, a wafer with awafer number W11 is held, and W11 is an unprocessed wafer. The transportdestination information 502 is exemplified in FIG. 16, and shows atransport destination process chamber for each wafer. The operationinstruction rule information 503 is exemplified in FIG. 18, anddescribes an operation instruction and a condition for following theoperation instruction. For example, an operation instruction “transportfrom the load lock 211 to the buffer room 212” means that theinstruction is followed when conditions “there is an unprocessed waferwhose transport destination is not the process chambers 205 and 206 inthe load lock 211 which is in vacuum”, “there is an available holdingstep in the buffer room 212” and “at least one hand of the vacuum robot217 is standing by” are met. The operation instruction information 506is exemplified in FIG. 17, and contains an operation instruction oftransportation and a wafer number of a transport subject. In theoperation instruction calculation 504, the device state information 501and the transport destination information 502 are referred to, anoperation instruction whose operation instruction conditions in theoperation instruction rule information 503 are all met is extracted, andthe operation instruction is output as the operation instructioninformation 506.

In the operation command generation 507, the operation instructioninformation 506 and operation sequence information 505 are input, anoperation command 508 is output, and the operation command 508 istransmitted to a machine unit. The operation sequence information 505 isexemplified in FIG. 19. The operation sequence information 505describes, about an operation instruction, specific operation contentsof each portion such as an operation of an atmosphere robot and a vacuumrobot, an open/close operation of gate valves between load locks, bufferrooms and process chambers, an operation of a pump that performs vacuumdrawing of the load locks, and means that operations are executedstarting from ones with smaller numbers described in operation ordercolumns. The operation sequence information 505 is defined for eachoperation instruction.

In the operation command generation 507, operation sequence data aboutan operation instruction is extracted from the operation sequenceinformation 505 about the operation instruction in the operationinstruction information 506, and the data is transmitted as an operationcommand to the machine unit starting from ones with smaller operationorder numbers.

Next, an embodiment of the transport destination deciding calculation405 shown in FIG. 4 is explained in detail with reference to FIG. 6.FIG. 6 is a figure showing a relationship between a process of thetransport destination deciding calculation 405, and input and outputinformation in detail. The transport destination deciding calculation405 is configured with three arithmetic operation processes ofunprocessed wafer amount calculation 605, allocation-subject processchamber calculation 607, and transport destination calculation 609.

In the unprocessed wafer amount calculation 605, device stateinformation 601 is input, and unprocessed wafer amount information 606is output. The unprocessed wafer amount information 606 is exemplifiedin FIG. 20, and shows, for each process chamber, the number ofunprocessed wafers whose transport destinations are the process chamber.Here, an unprocessed wafer is one on which a process is not completelyended in a process chamber. In the present embodiment, a state of awafer is managed by identifying it with three states “unprocessed”, “inprocess”, and “process completed”, and in this case, an unprocessedwafer means one the state of which is “unprocessed” or “in process”.Details of a process of the unprocessed wafer amount calculation 605 aredescribed below.

In the allocation-subject process chamber calculation 607, charge limitamount information 602, process chamber information 603 and theunprocessed wafer amount information 606 are input, andallocation-subject process chamber information 608 is output. The chargelimit amount information 602 is exemplified in FIG. 22, and means, foreach process chamber, an upper limit of the number of wafers in processin the process chamber, and unprocessed wafers that are transported tothe process chamber. The process chamber information 603 is exemplifiedin FIG. 15, and shows an operation status of each process chamber. Thestatus of “active” means that a process can be performed, and the statusof “inactive” means that a process cannot be performed. Theallocation-subject process chamber information 608 is exemplified inFIG. 21, and lists up process chambers that are candidates in allocatinga transport destination when calculating a transport destination of awafer. Details of a process of the allocation-subject process chambercalculation 607 are described below.

In the transport destination calculation 609, process subjectinformation 604, transport destination information 610 and theallocation-subject process chamber information 608 are input, and thetransport destination information 610 is updated. The process subjectinformation 604 is exemplified in FIG. 14, and describes a wafer numberthat identifies a process subject wafer. Details of a process of thetransport destination calculation 609 are described below.

Next, details of the process of the unprocessed wafer amount calculation605 shown in FIG. 6 are explained with reference to a flowchart of FIG.7. In the unprocessed wafer amount calculation 605, for each processchamber, the number of unprocessed wafers whose transport destinationsare the process chamber is computed. First, data about unprocessed waferamount information is cleared. Next, at a process step 701, all the datarepresenting portions other than the “load ports”, and the state of awafer of “unprocessed” or “in process” is extracted from device stateinformation. Then, at a process step 702, a piece of the data extractedat the process step 701 is selected, data about transport destinationinformation having a wafer number same as the wafer number of the pieceof the data is extracted, a number of a process chamber that is atransport destination of the data about the transport destinationinformation is acquired, and the number of unprocessed wafers with theprocess chamber numbers in the unprocessed wafer amount information isincreased by one. Next, at a process step 703, it is checked whether theprocess step 702 has been performed for all the data extracted at theprocess step 701, and if the process step 702 has been performed for allthe data, the unprocessed wafer amount calculation 605 ends. On theother hand, if the process step 702 has not been performed for all thedata, the procedure returns to the process step 702, and the processstep 702 and the subsequent processes are repeated.

Next, details of the process of the allocation-subject process chambercalculation 607 shown in FIG. 6 are explained with reference to aflowchart of FIG. 8. In the allocation-subject process chambercalculation 607, candidates of an allocated process chamber are decidedwhen deciding a transport destination of a wafer. First,allocation-subject process chamber information is cleared. Next, at aprocess step 801, all the process chambers with the statuses of “active”are extracted from process chamber information. Next, at a process step802, a piece of the data in the process chamber information extracted inthe process step 801 is selected. Data having a process chamber numbersame as a process chamber number of the selected piece of the data isextracted from unprocessed wafer amount information, and an unprocessedwafer amount of the data is acquired. Also, data having a processchamber number same as a process chamber number of the selected piece ofthe data is extracted from charge limit amount information, and a chargelimit amount of the data is acquired. Next, at a process step 803, theunprocessed wafer amount and the charge limit amount acquired at theprocess step 802 are compared with each other. When the unprocessedwafer amount is smaller than the charge limit amount, the procedureproceeds to a process step 804, and when the unprocessed wafer amount isequal to or larger than the charge limit amount, the procedure proceedsto a process step 805. At a process step 804, to make the processchamber selected at the process step 802 an allocation-subject processchamber, the process chamber number is added to the allocation-subjectprocess chamber information. Next, at the process step 805, it ischecked whether the process steps 802 and 803 have been performed forall the process chambers extracted at the process step 801, and if theprocess chamber steps 802 and 803 have been performed for all theprocess chambers, the allocation-subject process chamber calculation 607ends. On the other hand, if the process chamber steps 802 and 803 havenot been performed for all the process chambers, the procedure returnsto the process step 802, and the process step 802 and the subsequentprocesses are repeated.

Next, details of the process of the allocated transport destinationcalculation 609 shown in FIG. 6 are explained with reference to aflowchart of FIG. 9. In the transport destination calculation 609, atransport destination process chamber of a wafer to be charged in thedevice is decided. First, at a process step 901, a wafer number of awafer to be charged in the device is acquired. The specific process isthat data about wafer numbers not contained in transport destinationinformation are extracted from process subject information, data about awafer with the smallest wafer number is acquired therefrom, and thewafer is made a wafer to be charged in the device. Next, at a processstep 902, data about a wafer with the largest wafer number is extractedfrom the transport destination information, and a transport destinationprocess chamber of the data is acquired. Then, next at a process step903, all the process chamber numbers in allocation-subject processchamber information are extracted, and if there is a process chambernumber larger than the process chamber number acquired at the processstep 902, a process chamber with the smallest process chamber numberamong the process chamber numbers larger than the process chamber numberacquired at the process step 902 is made a transport destination processchamber. If there is not a process chamber number larger than theprocess chamber number acquired at the process step 902, a processchamber with the smallest process chamber number among all the processchamber numbers in the allocation-subject process chamber information ismade a transport destination process chamber. Lastly, at a process step904, the transport destination process chamber acquired at the processstep 903 is allocated as a transport destination process chamber of thewafer acquired at the process step 901, and is added to the transportdestination information. The algorithm of deciding the transportdestination explained in the present embodiment is merely an example,and the present invention is not limited to this algorithm. Anyalgorithm can be used as far as a transport destination of a wafer iscalculated by inputting the allocation-subject process chamberinformation calculated based on unprocessed wafer amount information.

Here, the device state information 601 and the process chamberinformation 603 explained in FIG. 6 are information obtained bymonitoring a machine unit, and are kept being updated, and the processsubject information 604 is downloaded from a host computer when acassette containing a process subject wafer arrives at a load port. Onthe other hand, the charge limit amount information 602 is calculated inadvance at the time the structure of the machine unit of the device isdecided. In the following, a method of calculating the charge limitamount information 602 is explained.

FIG. 10 is a figure that explains a relation between a process of chargelimit amount calculation, and input and output information. In chargelimit amount calculation 1004, process chamber information 1001, blockinformation 1002 and holdable wafer amount information 1003 are input,and charge limit amount information 1005 is output.

Here, a block is explained with reference to FIG. 25. A block is a unitthat segments several portions of a vacuum-side machine unit. Portionsconfiguring a block are a transport chamber, all the process chambersconnected to the transport chamber, and a load lock connected to thetransport chamber or a buffer room connected to the transport chamber.When a load lock is connected to the transport chamber, the load lock isincluded as a portion configuring the block, but a buffer room connectedto the transport chamber is not included. An example is a block 2503 ofFIG. 25. A load lock 2504 is connected to a transport chamber 2505, anda buffer room 2508 is also connected thereto. In this case, portionsconfiguring the block 2503 are the transport chamber 2505, the load lock2504, and process chambers 2506, 2507. Also, when two buffer rooms areconnected to a transport chamber, a buffer room on a side closer to aload lock is included as a portion configuring a block including thetransport chamber, and the other buffer room is not included in theblock. An example is a block 2502 of FIG. 25. The buffer room 2508, anda buffer room 2512 are connected to a transport chamber 2509. In thiscase, the buffer room 2508 on a side closer to the load lock 2504 isincluded in a block including the transport chamber 2509, and the bufferroom 2512 on a side far from the load lock 2504 is not included.Accordingly, portions configuring the block 2502 are the transportchamber 2509, the buffer room 2508, and process chambers 2510, 2511.Likewise, a block 2501 is configured with a transport chamber 2513, thebuffer room 2512 and process chambers 2514, 2515. The block is definedaccording to the above rules.

As explained above, the block information 1002 is information asexemplified in FIG. 24, and shows correspondence of each block andportions configuring the block. Also, the holdable wafer amountinformation 1003 is information as shown in FIG. 23, and shows thenumber of wafers that can be held in each block. The wafers can be heldin a load lock and a buffer room, and the holdable wafer amountinformation 1003 is the number of wafers that can be held in the loadlock and the buffer room configuring the block. Also, the holdable waferamount means the number of unprocessed wafers that can be held, and forexample, in a case that there are four holding steps in a buffer room,when two holding steps are for holding unprocessed wafers and the othertwo holding steps are for holding processed wafers, the holdable waferamount is two.

Next, details of the process of the charge limit amount calculation areexplained with reference to FIG. 11. First, at a process step 1101, aprocess chamber is selected from process chamber information, data aboutthe process chamber is extracted from block information, and a blocknumber of the data is acquired. Next, at a process step 1102, all thedata having the block number acquired at the process step 1101 isextracted from the block information, and the number of data setsrepresenting process chambers as portions are counted. That is, thenumber of process chambers configuring the block is counted. Next, at aprocess step 1103, data having the block number acquired at the processstep 1101 is extracted from holdable wafer amount information, and theholdable wafer amount of the data is acquired. Next, at a process step1104, a quotient is obtained by dividing the holdable wafer amountacquired at the process step 1103 with the number of process chambersacquired at the process chamber step 1102, and the value obtained byadding one to the quotient is recorded in charge limit amountinformation as the charge limit amount of the process chamber selectedat the process step 1101. Lastly, at a process step 1105, it is checkedwhether the processes of the process chamber steps 1102, 1103 and 1104have been performed for all the process chambers contained in theprocess chamber information. If the processes have been performed forall the process chambers contained in the process chamber information,the process ends, and if the processes have not been performed for allthe process chambers contained in the process chamber information, theprocedure returns to the process chamber step 1101, and the processchamber step 1101 and the subsequent processes are repeated.

Next, an embodiment of the transport destination deciding calculation405 shown in FIG. 4 is explained with reference to FIG. 26. Thetransport destination deciding calculation 405 is configured with threearithmetic operation processes of reservation information calculation2601, allocation-subject process chamber information calculation 2603,and transport destination calculation 2605.

In the reservation information calculation 2601, transport destinationinformation 2606, device state information 2607 and transport pathinformation 2608 are input, and reservation information 2062 is output.The transport destination information 2606 is exemplified in FIG. 16 asexplained above. Also, the device state information 2607 is exemplifiedin FIG. 13 as explained above. The transport path information 2608 isexemplified in FIG. 29, and lists up, for each process chamber, bufferrooms and load locks on a transport path of a wafer when the processchamber has become a transport destination. The reservation information2062 is exemplified in FIG. 30, and stores therein reservation status ofeach step, that is, each holding mechanism, provided in a room such as aload lock and a buffer room provided with a mechanism to a wafer. Here,the reservation state of each holding mechanism is indicated with eitherof “blank” and “wafer number”. “Blank” indicates that the holdingmechanism is not reserved, and “wafer number” indicates the holdingmechanism is reserved for a wafer with the wafer number. Details of aprocess of the reservation information calculation 2601 are describedbelow.

In the allocation-subject process chamber calculation 2603, thereservation information 2602 and process chamber information 2609 areinput, and allocation-subject process chamber information 2604 isoutput. The allocation-subject process chamber information 2604 isexemplified in FIG. 21, and lists up process chambers to be candidatesof a transport destination when calculating a transport destination of awafer. Details of a process of the allocation-subject process chambercalculation 2603 are described below.

In the transport destination calculation 2605, process subjectinformation 2610, the transport destination information 2606 and theallocation-subject process chamber information 2604 are input, and thetransport destination information 2606 is updated. The process subjectinformation 2610 is exemplified in FIG. 14, and describes a wafer numberthat identifies a process subject wafer. Details of a process of thetransport destination calculation 2605 are similar to the process of theflowchart in FIG. 9 explained above.

Next, details of the process of the reservation information calculation2601 shown in FIG. 26 are explained with reference to a flowchart ofFIG. 27. In the reservation information calculation 2601, for eachwafer, a transport destination process chamber and a holding mechanismthat the wafer goes through when the wafer is transported to the processchamber are reserved, or the reservations are cancelled. First, at aprocess step 2701, for each wafer, information of a transportdestination process chamber, and a holding mechanism that the wafer goesthrough when the wafer is transported to the process chamber isacquired. Next, at a process step 2702, for each wafer whose transportdestination has been decided and for which a holding mechanism has beenreserved, when the wafer is in process or the wafer has passed throughthe holding mechanism, the reservation of the holding mechanism iscancelled. Here, that the wafer has passed through the holding mechanismmeans that, after the wafer has once been transported to the holdingmechanism, the wafer has been transported out of the holding mechanismby a transport robot to be transported to another holding mechanism.Next, at a process step 2703, for a wafer with the smallest wafer numberamong unprocessed wafers whose transport destinations have been decided,and for which holding mechanisms have not been reserved, all the holdingmechanisms that the wafer goes through when the wafer is transported toa process chamber are reserved. Here, when a holding mechanism isreserved, all the holding mechanisms do not have to be reserved. Aholding mechanism provided in a buffer room that is closer to a loadlock among buffer rooms on a transport path connected to a transportchamber that transports to a transport destination process chamber or,when there is not a buffer room on a transport path, only a holdingmechanism provided in a load lock may be reserved. At a process step2704, it is checked whether all the holding mechanisms are reserved orwhether there is a wafer for which a holding mechanism is yet to bereserved. If either one of the above conditions is met, the reservationinformation calculation 2601 ends, and if neither of the conditions ismet, the process step 2701 is executed again.

Next, details of the process of the allocation-subject process chambercalculation 2603 shown in FIG. 26 are explained with reference to aflowchart of FIG. 28. In the allocation-subject process chambercalculation 2603, a process chamber to which a wafer can be transportedis extracted. First, at a process step 2801, an active process chamberis extracted. At a process step 2802, for each active process chamber,availability information of a holding mechanism of each load lock andbuffer room that a wafer goes through when the wafer is transported tothe process chamber is acquired. At a process step 2803, it is judged,for each process chamber, that the process chamber is not an allocationsubject when the number of available holding mechanisms provided in atleast either one of a load lock and a buffer room that a wafer goesthrough when the wafer is transported to the process chamber is one orless, and the process chamber is an allocation-subject process chamberat a process step 2804 when there is certainly more than one holdingmechanisms provided in a load lock and a buffer room that a wafer goesthrough when the wafer is transported to the process chamber. At aprocess step 2805, it is checked whether the process has been executedfor all the active process chambers.

Here, the device state information 2607 and the process chamberinformation 2609 explained in FIG. 26 are information obtained bymonitoring a machine unit, and are kept being updated. Also, the processsubject information 2610 is downloaded from a host computer when acassette containing a process subject wafer arrives at a load port.

Lastly, a display of the console terminal 103 shown in FIG. 1 isexplained with reference to FIG. 12. The console terminal 103 isprovided with an input unit such as a keyboard, a mouse, and a touchpen, and an output unit such as a display. The display includes an area1201 in which a control method is selected, an area 1202 that displays asummary of a device state, and an area 1203 that displays detailed dataabout the device state. In the area 1201 in which a control method isselected, a control method of either “manual” or “automatic” can beselected. Furthermore, when “automatic” is selected as the controlmethod, whether to respond to process time irregularity can be selected.The area 1202 that displays a summary of a device state displaysvisually the device and a position of a wafer so that it is possible tograsp easily where the wafer is. When the wafer moves, a displayposition of the wafer changes accordingly. Circles in the area 1202 inthe figure represent wafers 1204. Also, the area 1203 that displaysdetailed data about the device state displays details of a state of awafer in the device, and details of a state of a process chamber and atransport mechanism.

What is claimed is:
 1. A vacuum process device, the vacuum processdevice comprising: a load lock that takes in a work piece placed on anatmosphere-side to a vacuum-side; a plurality of process chambers thatare provided on the vacuum-side, and perform a predetermined process onthe work piece; a plurality of transport mechanism units provided with avacuum robot that performs receiving and passing of the work piece; aplurality of transport buffer units that perform relay-transporting ofthe work piece by interconnecting the transport mechanism units; aholding mechanism unit that is provided in the load lock and thetransport buffer unit, and holds a plurality of the work pieces; and acontrol unit that controls the receiving and passing, and therelay-transporting of the work piece, wherein the control unit holdsdevice state information that shows operation states of the processchambers, the transport mechanism units, the transport buffer units, andthe holding mechanism unit, and presence and absence, and a processstate of the work piece; computes based on the device state information,for each of the process chambers, the number of work pieces that are inprocess or are being transported to the process chamber where a processon the work pieces is planned and are not processed in the processchamber as the number of unprocessed work pieces; when the computednumber of unprocessed work pieces is equal to or larger than a chargelimit amount that is set in advance, computes transport destinationcandidates excluding a process chamber with the number of unprocessedwork pieces equal to or larger than the charge limit amount; andcomputes a transport destination of the work piece from among thetransport destination candidates.
 2. The vacuum process device accordingto claim 1, wherein the charge limit amount is set to a value obtainedby dividing the number of unprocessed work pieces that can be held in aholding mechanism unit provided in the load lock continuous to atransport mechanism unit connected to a process chamber or a transportbuffer unit on a side closer to the atmosphere-side continuous to thetransport mechanism unit with the number of all process chambersconnected to the transport mechanism unit connected to the processchamber, and adding one to an obtained quotient, or a value smaller thanthe value.
 3. The vacuum process device according to claim 1, whereinthe charge limit amount is decided based on the number of work piecesthat can be held in the holding mechanism unit.
 4. The vacuum processdevice according to claim 1, wherein the control unit has an input unitfor inputting data; and a method of computing a transport destination ofthe working piece responding to process time irregularity of the workingpiece can be selected with the input unit.
 5. A vacuum process method,the method comprising: controlling a load lock by taking a work piece bythe load lock placed on an atmosphere side to a vacuum-side; receivingand passing the work piece using a vacuum robot; relay-transporting thework piece by interconnecting transport mechanism units; and performinga predetermined process on the work piece in a process chamber, whereinat the receiving and passing, and the relay-transporting of the workpiece, the number of work pieces that are in process, and are beingtransported to the process chamber and are not processed is calculatedas the number of unprocessed work pieces for each of the processchamber, and when the number of unprocessed work pieces is equal to orlarger than a charge limit amount that is set in advance, transportdestination candidates excluding the process chamber are computed, and atransport destination of the work piece is computed from among thetransport destination candidates.
 6. The vacuum process method accordingto claim 5, wherein the charge limit amount is set to a value obtainedby dividing the number of unprocessed work pieces that can be held in aholding mechanism unit provided in the load lock continuous to atransport mechanism unit connected to a process chamber or a transportbuffer unit on a side closer to the atmosphere-side continuous to thetransport mechanism unit with the number of all process chambersconnected to the transport mechanism unit connected to the processchamber, and adding one to an obtained quotient, or a value smaller thanthe value.
 7. The vacuum process method according to claim 5, whereinthe charge limit amount is decided based on the number of work piecesthat can be held in the holding mechanism unit.
 8. The vacuum processmethod according to claim 5, wherein a control unit has an input unitfor inputting data; and a method of computing a transport destination ofthe work piece responding to process time irregularity of the work piececan be selected with the input unit.
 9. A vacuum process devicecomprising: a load lock that takes in a processed member placed on anatmosphere-side to a vacuum-side; a plurality of process chambers thatare connected to a transport chamber provided on the vacuum-side, andperform a predetermined process on the processed member; a plurality oftransport mechanism units provided with a vacuum robot that performsreceiving and passing, and transporting of the processed member; abuffer room that relay-carries the processed member by interconnectingthe transport mechanism units; a holding mechanism unit that is providedin the load lock and the buffer room, and holds a plurality of theprocessed members; and a control unit that controls the receiving andpassing, and the transporting of the processed member, wherein thecontrol unit reserves, for a processed member transported to the processchamber, the holding mechanism unit on a path to the process chamber,and decides a transport destination of a processed member to betransported next according to a status of the reservation.
 10. Thevacuum process device according to claim 9, wherein in deciding atransport destination of the processed member, when there is a processchamber such that a holding mechanism unit on a path to the transportdestination process chamber becomes reserved after reserving the holdingmechanism unit next or a holding mechanism unit of a load lock or abuffer room that the processed member goes through when the processedmember is transported to the process chamber becomes reserved, thecontrol unit decides a transport destination excluding the processchamber.
 11. The vacuum process device according to claim 9, wherein thecontrol unit judges it necessary to change allocation to a processchamber after an elapse of a certain length of time in a state that theholding mechanism unit in a buffer room or a load lock on a path to theprocess chamber to which a processed member is planned to be transportedis reserved or in a state that the number of holding mechanism units ona transport path of a processed member that are not reserved is equal toor smaller than one.
 12. The vacuum process device according to claim 9,wherein the control unit has an input unit for inputting data; and amethod of computing a transport destination of the processed memberresponding to process time irregularity of the processed member can beselected with the input unit.